Means for adjusting the lost motion of the valve actuation in internal combustion engines



Nov. 1, 1955 A. F. c. WENTE 2,722,204

MEANS FOR ADJUSTING THE LOST MOTION OF THE VALVE ACTUATION IN INTERNAL COMBUSTION ENGINES Filed June 4, 1954 2 Sheets-Sheet 1 ADOLF F. c. WENTE.

ATTORNEYS.

Nov. 1, 1955 A F c. wENTE 2,722,204

MEANS FOR ADJUSTING 'il-IE LOST MOTION OF THE VALVE ACTUATION IN INTERNAL COMBUSTION ENGINES Filed June 4, 1954 2 Sheets-Sheet 2 z A? 555mm" ADOLF F. C- WENTE.

BY M

A TTORNE YS United States Patent MEANS FOR ADJUSTING THE LOST MOTION OF THE VALVE ACTUATION IN INTERNAL COM- BUSTION ENGINES Adolf F. C. Wente, Stuttgart-Bad Cannstatt, Germany,

assignor to Daimler-Benz Aktiengesellschaft, Stuttgart- Unterturkheim, Germany Application June 4, 1954, Serial No. 434,559

Claims priority, application Germany June 5, 1953 Claims. (Cl. 123-90) My invention relates to means for adjusting the lost motion of the valve actuation in internal combustion engines in which the valve is actuated by the associated cam of a cam shaft through the intermediary of suitable means, such as a rocking lever. More particularly, my invention relates to adjusting means of the character indicated for four-cycle internal combustion engines having overhead valve-controlling means.

It is the object of the present invention to provide adjusting means offering a possibility of disposing the cam shaft at a close distance from the valve stem either directly thereabove or offset to the left or to the right. Further objects are to provide improved means for adjusting the lost motion of the valve actuation permitting to reduce the dimensions and the weight of the rocking lever interposed between the valve stem and the cam shaft.

Further objects of the present invention will appear from the description following hereinafter of two preferred embodiments of my invention, it being understood that such detailed description serves the purpose of illustrating the invention rather than that of limiting the same. In the drawings,

Fig. 1 illustrates a vertical, more or less diagrammatical section taken through the cylinder head of an internal combustion engine showing the valve in elevation and the adjusting means mounted thereon in section,

Fig. 2 shows a portion of Fig. 1 on an enlarged scale,

Fig. 3 is a horizontal section taken along line IIIIII of Fig. 2,

Fig. 4 is a sectional view similar to that of Fig. 2 of the upper end of a valve stem provided with another embodiment of the novel adjusting means, and

Fig. 5 is a horizontal section taken along line V-V of Fig. 4.

The cylinder head of the internal combustion engine is provided with an exhaust conduit 11 controlled by a poppet valve having a stem 12 and a head 13. The stem extends from the head 13 upwardly being guided in a bushing 14 and projecting above the cylinder head 10 for cooperation with suitable valve control means, such as a rocking lever 15 mounted to rock on a stationary fulcrum 16 and adapted to be depressed by a cam 17 of a horizontal cam shaft 18 which extends above the cylinder head 10. A helical spring 19 surrounding the upper projecting end of the valve stem 12 bears against the cylinder head 10 and against an annular disk 20 fixed to the valve stem 12 by means to be described hereinafter, such spring tending to keep the valve in the closed position shown. On revolution of the cam shaft 18, the cam 17 engages the upper face 21 of lever 15 and depresses the same causing the bottom face 22 of the lever to depress and thereby open the valve.

For the purposes of the present invention, the end of the valve stem 12 is threaded and provided with a longitudinal guideway. In the embodiment illustrated in Figs. 1, 2 and 3 such guideway is formed by a key slot 23 which extends from the end face of stem 12 downwardly to a point located substantially at the level of the disk 2,722,204 Patented Nov. 1,, 1955 20. i The annular disk 20 has internal threads and is screwed on the threaded end of stem 12 so as to rest on the helical spring 19. A cup-shaped nut 24- is screwed upon the end of the valve stem 12 and is provided with. a flattop face adapted to engage the curved bottom face 22 of the rocking lever 15. A- washer 25 on the. stem 12 is interposed between the disk 20 and the nut 24. The Washer has means which slidably engage the guideway to be thereby held against rotation on the stem 12. In the embodiment shown in Figs. 1, 2 and 3 such means is formed by an internal projection 26 of the washer 25. This projection engages the key slot 23. Preferably, the annular disk 20, the washer 25 and the nut 24 have a polygonal, for instance hexagonal shape adapted for engagement by a wrench for the purpose of adjustment indicated at 29, 30 and 31.

For the purpose of adjusting the lost motion of the valve actuation the operator must turn the disk 20 in clockwise direction while holding stem 12 against rotation by engagement of the washer 25 with a wrench. Such clockwise direction will relieve nut 24 from axial stress thus permitting a very accurate adjustment of the nut 24. Thereupon the disk 20 is again firmly screwed against the washer 25, whereby the latter is pressed against the nut 24 thus securing the same in position against accidental displacement. In this manner, the lost motion may be very accurately adjusted. Since the lever 15 is free from adjusting means, its dimensions and its consequent weight and mass may be reduced to a minimum.

The embodiment illustrated in Figs. 4 and 5 differs from that shown in Figs. 1, 2 and 3 in that the longitudinal guideway provided on the stem is formed by opposed recesses providing for opposed parallel plane faces 27 of the stem 12. The washer is provided with a slot 28 open at one end adapted to engage over the stem 12 snugly fitting on the faces 27. Hence, the washer may be laterally slid over the stem.

From the foregoing description it will appear that the rocking lever 14 is free from adjusting means and, therefore, may have minimum dimensions permitting the cam shaft 18 to be disposed at a comparatively short distance from the cylinder head 10. This is achieved in that the adjustment of the lost motion may be performed directly on the valve stem. The adjusting means comprise the threaded end of the valve stem 12 on which the springsupported disk 20 and the cup-shaped nut 24 engaging the free end of the valve stem are screwed. Moreover, the adjusting means comprise the washer 25 mounted on the valve stem for longitudinal movement, but held against rotation thereon, such washer being interposed between the spring disk 20 and the cup-shaped nut 24. Owing to such disposition and arrangement of the adjusting means, the customary wedge elements usually provided to secure the spring-supported disk on the valve stem are eliminated.

While I have described my invention with reference to two preferred embodiments thereof, I wish it to be clearly understood that the same is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

What I claim is:

1. In an internal combustion engine, the combination comprising a poppet valve having a stem, the end of said stem being threaded and provided with a longitudinal guideway, an internally threaded annular disk screwed upon said stem and adapted to rest on a helical spring, a cup-shaped nut screwed upon the end of said stem, and a washer on said stem interposed between said disk and said nut and having means slidably engaging said guideway to be thereby secured against rotation on said stem.

2. The combination claimed in claim 1 in which said guideway is formed by a key slot of said stem, said means being formed by an internal projection of said washer engaging said key slot.

3. The combination claimed in claim 1 in which said gnideway is formed by opposed recesses providing for opposed parallel plane faces of said stem, said washer being provided with a slot open at one end and adapted to he slid laterally over said stern engaging said faces.

4. The combination claimed in claim 1 in which said annular disk has a polygonal shape.

5. The combination claimed in claim 1 in which said disk and said washer have polygonal shapes.

References Cited in the file of this patent UNITED STATES PATENTS Roehrich Feb. 22, 1916 Kandarian Dec. 23, 1924 MacPherson Feb. 8, 1927 FOREIGN PATENTS Great Britain July 7, 1921 

